Rod screen



L. G. SYMONS Jan. 19, 1943.

ROD SCREEN led May 9; 1940 I r m 5 r n n I n .i

iiarweya jyezezar .Zarezz airy/720w; y M M Patented Jan. 19, 1943 RODSCREEN Loren G. Symons, Hollywood, Calif., assignor to NordbergManufacturing Company, Milwaukee, Wis, a corporation of WisconsinApplication May 9, 1940, Serial No. 334,141

16 Claims.

The invention relates to an improvement in screens, particularly of thebar or rod type.

One purpose is the provision of an improved rod for such screens.

Other purposes will appear from time to time in the course'of thespecification and claims.

The invention is illustrated more or less diagrammatically in theaccompanying drawing wherein:

Fig. 1 is a verticallongitudinal section through a rod screenillustrating the invention;

Fig. 2 is a partial longitudinal section illustrating the insertion of arod;

Fig. 3 is a section on the line 3--3 of Fig. 2;

Fig. 4 is an enlarged section on the line 4-4 of Fig. 2; and

Fig. 5 is a detail section through a part of the device.

Like parts are indicated by like symbols throughout the specificationand drawing.

Referring to the drawing, I indicates a side frame member, it beingunderstood that a pair of parallel side frame members may be employed toconstitute or form part of the screen deck. The deck as a whole may bevibrated in any suitable manner, for example by the unbalanced rotorgenerally shown at 15. The deck includes a plurality of transverselyextending frame members, including, for example, angles 2, 3 at the endsof the deck, an angle 4 interbers 9, H) are arranged back to back on theangles 4. Other channel members ll, upwardly concaved, are mounted onthe tops of the intermediate supports 5.

I find it practical to arrange the deck with a plurality of panels, eachsuch panel being formed to receive a plurality of rods l2, which will belater described in detail. The ends of the rods may be received intransversely extending rubber supports or cushions, or positioningmembers l3, provided with inclined spaced apertures l5, adapted toreceive the ends of the rods.

The supports l3 may be received in the end channels I of the cross framemembers or angles 2, at the feed end of the screen.

For the intermediate members 4 a different form of transverselyextending support may be employed, which is adapted to surround both thechannels 9 and I0. Such a member is illustrated at IS in Figs. 1 and 2and includes downwardly extending flanges l1, 18, each hav- 1 inginclined holes 20 to receive the rod ends. The face of the member I6toward the feed end of the screen may be beveled as at 2| to permit thematerial going over the screen to ride readily over it, and to protectthe end of the rod against excessive wear, which tends to take placewhere the flow of material is arrested. At the discharge end of thescreen I may employ a member 22 of rubber or the like, which is similarto the member IS, with a similar inclined face 2|, but is single in thatit has but one of the downwardly extending flanges l1 and is located inplace as for example by the smaller downwardly extending flange 23.

I find that there is a definite relation between the length and diameterof the rods, the hardness of the rods, etc., whichis in practiceexceedingly important. I find it well to employ normally straight rodsof a predetermined length. I have selected as one example a standardlength of 23%", which may be used for all types and sizes of screens. Inorder to prevent wear I find that the hardness of the rods should be notless than 300 Brinell. The ratio of rod length (L) to thickness (D)should be L/D not less than 60, and not more than 190. As an example ofa table of wire sizes, I may indicate the following:

Diameter (inches) Screen opening 5%", #11 wire .12 Screen opening #8wire .162 Screen opening #6 wire .192

Screen openings A", 1%" and #3 wire- .244 Screen openings /g", and A",#0 wire .307 Screen openings and 1", #000 wire .362

All of the above diameters are referred to a common length of 23%". Thislength is such that the ratio between diameter and length producessufficient resistance to fiexure in rods as small as A3" in diameter sothat they cannot be dislodged from their seats by the vibrating actionof the screen.

The fiexure of the rod necessary for placing it in the screen deck isapproximately 2 Rods after fiexure and before fiexure are shown in Fig.2. It will be understood that they must be flexed in order to permit theends to penetrate the apertures l5 or 20 of the various rubber supportsand positioning members. The rods are self-locking, due to theirresistance to fiexure. The material of the rod should also be such thatthe fiexure necessary to place it in position does not result in apermanent set or curvature of the rod. Stresses in the rod will be setup varying between 70,000 and 140,000 pounds per square inch, dependingupon the diameter of the rod. This represents the approximate yieldpoint in the material, which, if'exceeded, will result in a permanentset, but not necessarily in the failure of the material. I find itdesirable, in order to permit this fiexure, to employ steel of not lessthen .45 carbon, and I also employ manganese in addition, for example to.60. However, there is a, substantial possible variation of carbon andmanganese content.

Referring to Figs. 1 and 5, I illustrate a complete screen structure inwhich the rods it are illustrated as arched in individual panels A, B, Cand D, and in which the individual panels A, B, C and D are set atdifferent angles, whereby the screen is steeper at the feed end, beneaththe feed spout 50, and is most close to the horizontal at the oppositeor discharge end of the screen. The screen frame structure, includingthe side members I, is mounted upon a flexible link 5!, the details ofwhich do not form part of the present invention. It will be understood,however, that the feed end of the screen is vibratably supported by theinclined link 5| which has a rubber pad 52 at the top thereof, and asecond rubber pad 53 at the bottom thereof, the entire structure beingheld together, for example, by

bolts 54 and flexible rubber bushings 55. At

either side of the screen deck a spring 56, seated 30 between a framemember 51, secured to the base 62 and the screen deck, serves to cushionthe movement of said screen deck and link 5|.

The opposite end of the screen deck may be supported for example by atension member or rod 58, of which one may be located at each side ofthe screen, such rod having an upper washer 59 and a coil spring 60,compressed between such washer and the top SI of any suitablesurrounding outside housing or base 62.

Any suitable vibration producing means, which do not of themselves formpart of the present invention, are indicated as at I5, and will not bedescribed in detail. It will be understood, however, that 15 indicatesan unbalanced 45 rotor, which is unbalanced when rotated, and which maybe rotated by any suitable motor not herein shown, whereby vibration isimparted to the screen structure.

The change in angle as the material travels down the inclined surface ofthe screen decreases the gravital feed from the feed to the dischargeend of the screen and gives a quick settling action, with relative fasttravel, at the feed end, and slower travel, and complete screeningseparation, at the discharge end.

It will be realized that, whereas I have described and illustrated apractical and operative device, nevertheless many changes may be made inthe size, shape, number and disposition of parts without departing fromthe spirit of the invention. I therefore wish the description anddrawing to be taken as in a broad sense illustrative 01' digrammatic,rather than as limiting me to the precise showing.

It will be realized, for example, that the invention is not limited to arod of specific cross sectional shape. Whereas a round rod may beconvenient or preferable, a square bar or rod otherwise formed may alsobe employed. It will be understood also that, in place of a rod, I mayemploy a relatively flat member, such for example as a perforated orforaminous plate. The same factors apply.

assass n and 22, with the intermediate parts of the rods positioned inslots or concave apertures in the intermediate rubber supports 11. Therods are thus arched and held firmly in position and are laterallyspaced in relation to each other, and

vibration or displacement is prevented.

The arrangement of the panels to form a convex screen, or a screen witha varying angle from the horizontal, is highly desirable. The materialis fed partially by gravity along the initial or more highly inclinedpart of the deck, as

will be clear from Fig. 1, gravity supplementing the conveying action ofthe vibration of the screen in response to the rotation of the member15. As the fines pass through the initial part of this deck, a slowingof the movement, or

a settling action, is desirable, and this is obtained by the relativelyfiat angle of the discharge portion of the deck.

It will be observed that the rods I! may be uniformly spaced by theirpenetration in the end apertures 20, as shown in Figure 3, and also bytheir penetration in slots or grooves in the tops of the transverseintermediate members 'Il. Thus, once the rods are clamped in position,they are firmly locked in proper spaced relationship.

I claim:

1. A vibratory screen deck including side frame members and transverseconnecting members, and a plurality of screen panels on said 40 deck,each such screen panel including a plurality of longitudinally extendingwires, said wires being arched to form a transversely extending convexsurface for said panel, the panels being located at different angles inrelation to the horizontal and being arranged to form a generallyconcave screening surface, and upstanding bailles transversely extendingacross the screen along the abutting edges of adjacent panels, the feedface of said baflies being inclined.

2. A vibratory screen deck including side frame members and transverseconnecting members, and a plurality of screen panels on said deck, eachsuch screen panel including a. plurality of longitudinally extendingwires, said wires being arched to form a transversely extending convexsurface for said panel, the panels being located at different angles inrelation to the horizontal and being arranged to form a generallyconcave screening surface, the angle of the screening surface of thedeck, taken as a whole, diminishing from the feed end to the dischargeend of the deck, and upstanding baflles transversely extending acrossthe screen along the abutting edges of adjacent panels, the feed face ofsaid baifles being inclined.

3. A screen rod formed of steel having a hardness of not less than 300Brinell and having a ratio of length to thickness of not less than 60and not more than 190, and a yield point sufliness of not less than 300Brinell and having a ratio of length to thickness of not less than 60and not more than 190, and a yield point sufllcient to permit a fiexureof not less than 2 without permanent set in a length of in the order oftwo feet, said rod being formed of a steel of a-carbon content of notless than 0.45 and of the general order of 0.60.

5. A generally rectilinear screen rod formed of steel having a hardnessof not less than 300 Brinell and having a ratio of length to thicknessof not less than 60 and not more than 19.9. and a yield point suflicientto permit a fiexure'of not less than 2 without permanent set in a lengthof in the order of two feet.

6. A generally rectilinear screen rod formed of steel having a hardnessof not less than 300 Brinell and having a ratio of length to thicknessof not less than 60 and not more than 190, and a yield point sufficientto permit a i'lexure of not less than 2%" without permanent set in alength of in the order of two feet, said rod being formed of a steel ofa carbon content of not less than 0.45 and of the general order of 0.60.

7. In combination with a rod screen deck and means for vibrating it, ascreen rod formed of steel having a hardness of not less than 300Brinell and having a ratio of length to thickness of not less than 60and not more than 190, and a yield point sufficient to permit a flexureof not less than 2 without permanent set in a length of in the order oftwo feet.

8. In combination with a rod screen deck and means for vibrating it, ascreen rod formed of steel having a hardness of not less than 300Brinell and having a ratio of length to thickness of not less than 60and not more than 190, and a yield point sufiicient to permit a fiexureof not less than 2%" without permanent set in a length of in the orderof two feet, said screen rod being generally rectilinear, and supportsfor said rod, on said deck, adapted to receive the opposite ends of saidrod, said rod being insertable and removable by flexure into saidsupports.

9. In combination with a rod screen deck and means for vibrating it, ascreen rod formed of steel having a hardness of not less than 300Brinell and having a ratio of length to thickness of not less than 60and not more than 190, and a yield point sufiicient to permit a flexureof not less than 2%" without permanent set in a length of in the orderof two feet, said screen rod being generally rectilinear, and supportsfor said rod, on said deck, adapted to receive the opposite ends of saidrod, said rod being insertable and removable by fiexure into saidsupports, and

means for maintaining such rod in fiexure on said deck.

10. In combination with a rod screen deck and means for vibrating it, ascreen rod formed of steel having a hardness of not less than 300Brinell and having a ratio of length to thickness of not less than 60and not more than 190, and a yield point sufficient to permit a fiexureof not less than 2 /2" without permanent set in a length of in the orderof two feet, said screen rod being generally rectilinear, and supportsfor said rod, on said deck, adapted to receive the opposite ends of saidrod, said rod being insertable and removable by flexure into saidsupports, and means for maintaining such rod in fiexure on said deck,and upwardly flexed in relation to said deck.

11. A vibratory screen deck including side frame members, and transverseconnecting members, and not less than three screen panels on said deck,each such screen panel including a plurality of longitudinally extendingwires, said wires being arched to form a transversely extending convexsurface for each said panel, said panels being located at. difierentangles in relation to the horizontal and being arranged to form agenerally concave screening surface.

12. A vibratory screen deck including side frame members, and transverseconnecting members, and not less than three screen panels on said deck,each such screen panel including a plurality of longitudinally extendingwires, said wires being arched to form a transversely extending convexsurface for eachsaid panel, said panels being located at differentangles in rela-- tion to the horizontal and being arranged to form agenerally concave screening surface, the panel nearest the feed end ofthe screen being the most highly inclined, the inclination of the panelsfrom the horizontal being reduced progressively from the feed to thedischarge end of the screen.

13. A vibratory screen deck including side frame members, and transverseconnecting members, and not less than three screen panels on said deck,each such screen panel including a plurality of longitudinally extendingwires, said wires being arched to form a transversely extending convexsurface for each said panel, said panels being located at differentangles in relation to the horizontal and being arranged to form agenerally concave screening surface, and agitating baflies transverselyextending across the decks between each adjacent pair of panels, saidbafiies being of sufficient height to impart a substantial agitation tothe material passing thereover, the convexity of the individual panelsbeing suflicient to vary substantially the angular relation of the feedand discharge end of each panel to the horizontal.

14. A vibratory screen deck including side frame members, and transverseconnecting members, and not less than three screen panels on said deck,each such screen panel including a plurality of longitudinally extendingwires, said wires being arched to form a transversely extending convexsurface for each said panel, said panels being located at differentangles in relation to the horizontal and being arranged to form agenerally concave screening surface, the panel nearest the feed end ofthe screen being the most highly inclined, the inclination of the panelsfrom the horizontal being reduced progressively from the feed to thedischarge end of the screen, and agitating baflles transverselyextending across the decks between each adjacent pair of panels, saidbaffles being of sufficient height to impart a substantial agitation tothe material passing thereover, the convexity of the individual panelsbeing sufficient to vary substantially the angular relation of the feedand discharge end of each panel to the horizontal.

15. A vibratory screen deck, including not less than three screen panelson said deck, each such screen panel being arched to form a transverselyextending convex surface for each panel, said panels being located atdifferent angles in relation to the horizontal and being arranged toform a generally concave screening surface, the panel nearest the feedend of the screen being the most highly inclined, the inclination of thepanels from the horizontal being reduced progressively from the feed tothe discharge end of the screen, the convexity of the individual panelsbeing sufficient to vary substantially the angular relation of the ieedand the discharge end of each panel to the horizontal.

16. A vibratory screen deck, including not less than three screen panelson said deck, each such screen panel being arched to form a transverselyextending convex surface for each panel, I

said panels being located at different angles in relation to thehorizontal and being arranged to form a generally concave screeningsurface, the panel nearest the feed end of the screen being the mosthighly inclined, the inclination of the panels from the horizontal beingreduced progressively from the feed to the discharge end of 10 agitationto the material passing thereover.

LOREN G. BYMONS.

